1. Field of Invention
The present invention relates to a removable lid for a cup. The lid being especially suited for disposable cups, to fit tightly over the top opening of a cup, which typically contains coffee or other beverages. The lid of the present invention is intended to limit and prevent unwanted spillage of the contents of the cup while allowing the user to drink the contents while the lid remains on the cup. The present lid being simple and inexpensive to manufacture, competitive with cup lids without splash-proof capabilities.
2. Art Related to the Invention
Splash-proof lids for drinking cups to prevent unwanted loss or spillage of the contents of the cup that occurs when the cup is unintentionally moved are well known. Splash-proof cup lids with baffles are disclosed in prior patents including U.S. Pat. Nos. 6,488,173 and 6,305,571. However, these disclosed lids require multiple steps of assembly, are not unitary lids and thus are expensive, complicated to assemble and manufacture, and do not solve the problems addressed by the present invention.
Another example of a splash-proof lid is described in U.S. Pat. No. 6,811,049, which discloses a one-step molding process for forming a lid, whereby a chamber is created by rotating a bottom lid section against the underside of the lid. However, to form the chamber, an edge of the bottom lid section must mate with the circumferential snap-fitting portion of the lid. Not only is the chamber not sealed, but the integrity of the snap-fitting relationship between the cup and underside of the lids is interrupted, allowing for leaks. A preferred embodiment requires the bottom lid section must snap to the underside of the lid. The lid does not mate as a unitary layer with the cup along the entire snap-fitting portion and therefore compromises the integrity of the seal between the lid and the cup.
U.S. Patent Application Publication No. US 2006/0005369, discloses a cup lid with two snap together pieces to form a removable plug. This apparatus is expansive to assemble and manufacture, and, likewise, does not solve the problems addressed by the present invention.
A well-known method of manufacturing cup lids of the type used for coffee to-go cups and soft drinks is by vacuum forming, a plastic thermoforming process that involves forming thermoplastic sheets into three-dimensional shapes through the application of heat and pressure. This vacuum forming allows cup lids to be manufactured very inexpensively, provided the lid can fit within a clamshell type molding system. In general terms, vacuum forming refers to sheet forming methods, including drape forming, which is one of the most popular. Basically during vacuum forming processes, plastic material is heated until it becomes pliable, and then it is placed over a mold and drawn in by a vacuum until it takes on the desired shape. Vacuum thermoforming is used for producing plastic parts that have sharp details, close mold tolerances and fit to specific products.
As well know in the art, during the vacuum forming process, a sheet of heated plastic material is placed over a male or female mold. The mold then moves towards the sheet and presses against it to create a seal. Next, the application of a vacuum draws out the air between the mold and the sheet so that the plastic conforms to the mold exactly. When the curing temperature is reached and the piece is formed, air blows back into the mold and separates the new part from the mold. This process resembles the two potions of a clamshell that close upon one another. Articles suitable for this process must be formed of a single piece so that only one close and open sequence is required to completely form the article.
An advantage of the vacuum forming process is that plastic parts can be made with close mold tolerances and details for friction-fit assembly. Sharp, precise detail is available for many products, which makes vacuum formed plastics an attractive alternative to other molding processes.
There is a need for a simplified splash-proof lid, which can function with a conventional disposable cup, which is easy and inexpensive to manufacture, stack, ship, easy to use, and aesthetically pleasing to a user.
Therefore, it is an object of the present invention that a unitary lid be manufactured by vacuum form process or similar process that is inexpensive to make.
It is another object of the present invention that a splash-proof lid have a chamber in fluid communication with a drinking hole and the interior of the cup. It is another object of the present invention that the peripheral edge of the lid be in continuous contact with the cup edge.
It is an object of the present invention that the lid be a single or unitary piece that does not require assembly.
It is another object of the present invention that the lid may be made by any of the manufacturing processes known in the art.
It is another object of the present invention that the lid be manufacturable with a clamshell mold system.
It is another object of the present invention that the lid be disposable.
It is another object of the present invention that the lid be re-closeable.
It is another object of the present invention that the lid be non-disposable.
It is another object of the present invention that the lid be airtight.
It is another object of the present invention that the closing means be removable after placement in the well.
It is another object of the present invention that the lid seal on the cup and be drip free.
It is another object of the present invention that the lid seal on peripheral edges of the top of the cup.
It is another object of the present invention that a plug be detachable for insertion in a well to form a chamber.